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Metro Detroit Metalworking Club |
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PRESIDENT’S MESSAGE I am pleased and proud that
club members are taking the initiative. Carl Gross is bringing in a
speaker for the Nov 8th meeting. He is Chris Gogola, Adhesive
Specialist from Loctite Corporation. He promises a fun presentation and
free samples. Thank you, Carl. MINUTES
There were 16 members
and two guests. I started by mentioning the club book was again available.
Two guests introduced themselves; John Gore and Bob Fisher.
We would welcome them as members.
We had a free form discussion about tapping and what you can do
when a tap breaks. Alum in water was proposed by Don Foren as a way
to eat the steel tap but leave the aluminium work piece. Someone
else mentioned that a carbide end mill or carbide drill will chew through
the tap. We were informed
about forming taps and metric threads.
John O. mentioned the value he found in aluminium angle that had
4x4” legs and ½” thickness, but complained that it had to be bought
20 feet at a time. A member proposed that the club could buy pieces that
long and sold to several members. Good idea – the club can do what
individuals can’t afford.
We then went to show & tell.
Bert
Campbell made a
big radius cutter for his lathe. He needed to make mandrels for a pipe
bending machine he is making. He reports spending all of $1 and about a
day of work to make it. Bert may bring in the pipe bender next meeting.
Ron Schmidt made a mill head for a 3D duplicator. He did the designed as well as built it. He has about 40-50 hours in it.
Bob
Furman brought
in a beautiful model engine that also runs. He proved it. It’s a
hit-and-miss type of 1” bore that burns white gas and used WD-40 for
lubrication. It was a kit that cost about $250 and took 6 years to
build. (I hope it doesn’t take that long for his next Show &
Tell). Bob claims it was an interesting project and plans to build a
small generator for the engine to drive.
James
Howard brought in
materials for and provided a review of the common problems causing
malfunction in the operation of a blowtorch. The problems and
solutions, in order of frequency are; 1. Hardening of the spring-loaded leather shutoff gasket located on
the bottom of the plunger assembly, due to years of immersion in the fuel,
results in failure to maintain fuel tank pressure and frequent leakage of
fuel up into and beyond the plunger mechanism, a hazardous condition. The
gasket is made of 1/4" thick by 3/16" diameter leather,
mounted in the spring-loaded brass fitting with the flesh side upward,
i.e. toward the plunger orifice providing the pressurization. This
provides the surface necessary for proper sealing against leakage. He
recommended that anyone making this repair fill the tank with fuel,
pressurize the system and determine for at least 12 hours, with the
blowtorch left outside, that there is no leakage of fuel nor loss of
pressure. 2. Wear and deterioration of the leather gasket located on the
pressurization plunger mechanism results in failure to pressurize the
tank. This gasket is made of very thin leather of a nominal 1"
diameter and arranged on its metal mandrel with the flesh side out, providing
proper sealing function during plunger operation. Insertion of this
replaced gasket assembly into the neck of the plunger tube is extremely
difficult, even when properly greased and shaped, with serious danger of
cutting the leather on the lead edge of the plunger cylinder. James
finally hit upon the idea of shaping the flat leather disc to its ultimate
skirted shape by pulling the plunger assembly backwards into an
outside cut rule die cylinder of 7/8" outside diameter. The
bevelled edge provides a perfect lead for the greased leather disc to be
pulled into the required shape. 3. Cracking or deterioration of the seal between the plunger assembly
and the tank fill orifice results in failure to maintain pressure. This
gasket, of thin asbestos material, can be punched with rule die punches,
taking care to punch the ID hole first, because the thin wall will be
fractured if the OD blank is punched first and then the ID punch
applied to the blank. James has all these leather and rule die
punches and offered them to anyone needing them. 4. James recommended that members use low volatility fuel, such
as Coleman Fluid or Wal-Mart Camp Fuel (at half the price) for use inside
of a home or garage. These fuels do not present the vaporous fuel danger
that all gasolines have. This danger results from unexpected (and very
infrequent) failure of the shutoff gasket of a pressurized tank, allowing
gasoline and its heavy vapours to advance across the bench and onto
the floor to some household source of ignition. This danger could be relieved
if a user released pressure in the tank after every use, not likely for
most ordinary users.
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